Analyzing the circuits of neurons responsible for coding wavelength information will require detailed information on the populations of functional classes of cells. The goldfish retina serves as a useful model of both CNS processing and trichromatic coding. We intend to investigate the distributions and chromatic inputs of populations of retinal neurons in the goldfish with microchemical techniques. Isolated retinas will be incubated with tritiated gamma aminobutyric acid, glycine or RNA precursors (uridine, cytidine) during stimulation with steady or amplitude modulated colored lights, with or without adapting backgrounds and special patterns. Light-induced uptake will be assayed autoradiographically in serial radial and tangential sections by light microscopy and electron microscopy. Analysis will center on bipolar, amacrine and ganglion cell populations with emphasis on describing: (1) classes of chromatically responsive neurons; (2) the distributions of classes of neurons over the retina; and (3) synaptic connections made by identified neurons with surrounding cells.